As shown in FIG. 1, a conventional water jets cutting machine 1 includes a first rotating seat 11, a second rotating seat 12 rotatably connected to the first rotating seat 11, and a water jets cutting head 13 disposed on the second rotating seat 12. The first rotating seat 11 is driven by a first motor 14 to rotate about a first rotation axis (A). The second rotating seat 12 is driven by a second motor 15 to rotate about a second rotation axis (B). The first and second rotation axes (A, B) intersect each other and form an included angle therebetween. The water jets cutting head 13 is moved by the first and second rotating seats 11, 12 to be tilted to an inclination angle relative to the first rotation axis (A) for processing and producing a beveled surface.
However, during a cutting operation, factors, such as the positioning accuracy of the connecting mechanism of the first and second motors 14, 15, the material of abrasive particles, conditions of water jets devices, water jets head moving conditions, materials of machining parts and work pieces, etc., may affect the position of the water jets cutting head 13 so that the inclination angle of the water jets cutting head 13 is deviated from a assumed predetermined angle, thereby losing machining accuracy. Because the conventional water jets cutting machine 1 operates at a high cutting speed, flatness of the cut surface and/or perpendicularity between two planes are liable to fall out of an acceptable tolerance range, thus lowering accuracy of product quality.